The invention relates to a pump device for the hydraulic actuation of a valve, especially employed in the production of crude oil or natural gas, as a safety valve assigned to a pipeline or to a tree, with a piston-cylinder unit from which hydraulic fluid can be pumped under pressure in the direction of the valve.
Corresponding pump devices are known from practice, which are generally arranged far away from the actual valve and do not just supply it with hydraulic fluid, but also other equipment, in particular for crude oil or natural gas production. The appropriate valve is in this respect assigned to a pipeline or similar facility as a safety valve and is generally termed a downhole safety valve. In marine crude oil or natural gas production it is arranged along the pipeline and below the surface of the sea and is used for closing the pipeline in the case, for example, of a leak or similar problem.
With such safety valves it has however been found that often a leak occurs and already after a relatively short time a corresponding hydraulic fluid has run out, even out of a corresponding storage container. In addition a hydraulic fluid under pressure cannot be passed specifically to a certain safety valve at the point of application or relatively near to the safety valve, but rather generally long hydraulic fluid pipes are required, whereby at the most an appropriate reservoir for hydraulic fluid is arranged where applicable at the point of application at the safety valve. However, also here the appropriate leakage problems occur.